Vulcanized-rubber composition and method of preparing same.



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HEN'RY ALFEED GARDNER, 0F W'ASHINGTGN, DESTHJEGT 0E CfiL'fihllbllQr.

VULGAIt'IZED-RULBBER CGMPGSITION AND METHOD OF PEEPAEEN'G} SALME,

No Drawing.

To all whom it may concern:

Be it knownthat l, HENRY A. GARDNER, a citizen of the United States, residing at lVashington, in the District of Columbia, have invented certain new and useful lmprovements in Vulcanized-Rubber Compositions and Methods of Preparing Same, of which the following isa specification.

In my prior Patent No. 1,216,980, patented February 20, 1917, I have disclosed and broadly claimed a composition of matter comprising an organic vehicle, including rubber, and a mineral pigment consisting of or containing a substantial proportion of an insoluble compound of zirconium. As pointed out in saidpatent, such zirconium compounds are useful as colorants for rubber and serve to increase its tensile strength My investigations have shown that insoluble compounds of zirconium in a state of fine subdivision, are remarkably efficient not only as rubber colorants, but for the purpose of preparing vulcanized rubber articles pols sessing a very high tensile strength and like- Wise a high degree oi toughness, connoting excellent Wearing qualities. lit appears i'urther that these zirconium compoundspossass a distinct value as ace'lerants in the vulcanizing process itself.

lhe present application relates to the of vulcanizing rubber, and the invention comprises vulcanized rubber articles having as one of their components an insoluble compound of zirconium. The invention com prises also the method of preparing such vulcanized rubber articles.

I have demonstrated that the extraordinary hiding power possessed by finely-divided zirconium compounds is strongly evidenced in rubber compositions; and by the use of such pigments, or pigment-mintures, in proper proportions, 1 am able to prepare rubber articles possessing charac teristic degree of opacity, and an unusually light color in case White zirconium igments are used. This opacity, as well as t 1e mash ing of the original color ofthe rubber, is

attributable, as disclosed in my pat out above mentioned, to the high l active den in index of zirconium compounds, thi

some cases, for example zirconium ing as high as 2.20. lhus who compounded on the rolls in the usual mam her With a suiiicient proportion of a suitable finely-divided artificial or i l a" use compound, sucl'. so

Specification of Letters Patent.

a lication filed July 31, 191?.

pa rts o" Patented Nov 23d, Serial No. 183,772.

tioned, the dark color of the rubber is quickly obscured and an. opaque rubber co1nposition is formed. Moreover, since the zirconium compounds are not afl'ected by the sulfur usually incorporated in such mixtures With a view to vulcanization, the light color and opaque character oi the composition are found to be very persistent and are not materially modified by the vulcanizing process.

Among the insoluble zirconium componds, I'prefer to use the oxid, native or produced through precipitation methods; the silicate, including ground native silicates and silicious deposits; and such combined pigments as are described in my prior patent above mentioned, according to which zirconium oxid is precipitated upon or intimately commingled with base pigments of lower refractive index, such as zinc oxid, silica, barium sulfate and the like.

The following is an illustrative example of the application of my method to the preparation of a vulcanized rubber suitable for various purposes: 200 parts by Weight of Washed rubber are Worked on the rolls until the mass becom soft and receptive of mineral 7. ere are then added about 1G0 any suitable zii"osmium-con 'ning COZHPUL L, for example zirconium 0nd in a state oi fine subdivision, also about preferably also the usual genie or organic accelerators.

is continued until a thoroughly homogeneous plastic mass is produced. Ur incorporate with the rubber a prec reed mixture of a zirconiurn-containing pigment with an organic vehicle, for err ample such mixtures as are referred to in my Patent No. 1,216,980. l may also add any suitable colorant for imparting a red, black, brown or other color to the composi tion. The may then be shaped and vulnor.

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tam (lollef nnnera it We time required for VUlC ll- Ill or chemical changes of a little-understood nature, these changes takin place during the steps of incorporating t e material, or of vulcanizing, or during both of these operations, With the resulting formation of a rubber composition having an extremely high tensile strength, and a high degree of toughness, this last-mentioned quality being of particular value under such exacting conditions as the use of the vulcanized com osition for automobile tire treads and the li e.

I claim 1. The method of preparing a vulcanized rubber composition, which consists in incorporating a finely-divided insoluble zirconium compound with rubber, and vulcanizing the composition.

2. A vulcanized rubber composition containing a finely-divided insoluble zirconium compound.

3. A vulcanized composition characterized by its high tensile strength and toughness, and by the presence therein of a finely divided insoluble zirconium compound.

In testimony whereof, I aflix my signature.

HENRY ALFRED GARDNER.

Gupta 0! this patent my be obtained for five cents each, by addressing the "Commissioner of Patents, Washington, D. 0. 

